Smoothing and/or lapping tool particularly for finishing stone materials

ABSTRACT

The present invention relates to a finishing and/or polishing block-like tool of abrasive material, which includes at least one front working portion ( 2, 2   a ) and at least one rear portion designed to be anchored to a working head of a honing machine or a handle rear portion ( 3, 3   a ), the at least one front working portion ( 2, 2   a ) comprising:
         at least one first brushing working portion ( 4, 4   a ) including a plurality of bristle elements ( 5, 5   a ) each extending from the rear portion ( 3, 3   a ) through a length many times greater than the thickness thereof; and   at least one second working portion ( 6, 6   a ) including depressions ( 7, 7   a ) separated by at least one raising zone ( 8, 8   a ) having size many times greater than the thickness of one bristle element.

FIELD OF INVENTION

The present invention relates to a smoothing and/or lapping tool, particularly, but not exclusively, suitable for finishing workings of natural or artificial stone, ceramic or the like materials.

BACKGROUND OF INVENTION

Stone, porcelain, and not-porcelain ceramic materials are generally polished by using substantially rigid working tools having a Shore B hardness ranging from 70 to 90 degrees. Such tools comprise abrasive granules incorporated in a matrix including a cement binder, such as magnesium oxychloride, or a resin binder, e.g. polyester, polyurethane and epoxy resins; and fillers, e.g. iron carbonates and/or oxides, aluminium oxides, silicon carbides and the like.

Such granular abrasives, which are generally used with a granule size ranging from 36 to 1800 mesh, allow various hard materials to be worked, thereby obtaining bright surfaces thereon.

Tools including a rubber binder and having a Shore B hardness of 20 degree, and brushes including Nylon® as a binder have already been proposed. Such brushes make it possible to carry out surface workings with a high level of homogeneity in the surface finishing thereof. “Turtle” tools have also been proposed that are quite rigid, and thus they require to be mounted on resilient supports.

Honing machines have also been proposed which are provided with a plurality of different-type tools designed to carry out a so-called “mirror-like” or “undulated” surface finishing. The combined use of tools of different type from one another, however, causes sometimes defects to be formed on the materials, especially if single working step is carried out on the material. This means that in order to obtain an optimum surface finishing working two or three smoothing/lapping steps are to be carried out, and this of course heavily affects the working costs.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide a smoothing/lapping tool comprising portions of different hardness one with respect to the other, thereby being suitable for selectively work different surface portions of a slab or block of material.

Another object of the present invention is to provide a tool which is suitable for carrying out both finishing and polishing workings.

These and still other objects, which will become better apparent below, are achieved by a finishing and/or smoothing block-like tool of abrasive material, which comprises at least one front working portion and at least one rear portion designed to be anchored to a working head of a honing machine or a handle rear portion, said at least one front working portion comprising:

-   -   at least one first brushing working portion including a         plurality of bristle elements extending from said rear portion         through a length many times greater than the thickness thereof;         and     -   at least one second working portion including depressions         separated by at least one raising zone having size many times         greater than the thickness of one bristle element.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects and advantages of a smoothing and/or lapping tool according to the present invention will better appear from the following detailed description of specific embodiments thereof, the description being made with reference to the accompanying drawings, in which:

FIGS. 1 and 2 are plan and side views, respectively, of a tool according to a first embodiment of the present invention; and

FIGS. 3 and 4 are a plan view and a cross-section view taken along the line III-III of FIG. 3, respectively, of a second embodiment of a tool according to the present invention.

In the set of drawings, equal or similar parts or components are marked with the same reference numerals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference first to FIGS. 1 and 2, a first embodiment of finishing and/or smoothing tool 1 according to the present invention has been shown, which is shaped as a substantially parallelepiped block, preferably a rectangular block, of abrasive material. Block 1 comprises a front working portion 2 and a rear portion 3. The latter can be handle-shaped for manual use of the tool, or shoe-shaped to be anchorable to a working head of a honing or polishing machine (not shown in the drawings), as it is well known in the art.

The front working portion 2 includes one or more brushing working areas 4 having a plurality of bristle elements 5 extending or protruding from the rear anchoring portion or handle 3 for a length many times greater (typically from 5 to 10 times) than maximum thickness or transversal dimension of each bristle element. Advantageously, the brushing working portion or portions is/are spaced apart and extend/s so as to delimit a continuous working front extending throughout the length and, preferably, the width of the front working portion 2.

The front working portion 2 also has a plurality of working areas 6, each including depressions 7 separated by raising or in relief areas 8 each extending through an area many times greater (typically from 5 to 10 times) than the thickness of a bristle element.

Advantageously, the working area/s 6 is/are spaced apart and/or extend/s so that the areas in relief 8 thereof form all together a continuous or uninterrupted working front extending throughout the length and, preferably, the width of the front working portion 2.

FIGS. 3 and 4 show an annular-shaped finishing and/or polishing tool 1 a which includes a rear portion 3 a and a front working portion 2 a. The latter comprises one or more brushing working areas 4 a including a plurality of bristle elements 5 a, and one or more working areas 6 a provided with a plurality of reliefs or plugs 8 a separated by depressions 7 a from one another. The series of reliefs 8 a alternate with bristle elements 5 a, each series of reliefs 8 a and bristle elements being arranged along respective concentric circumferences. In the embodiment shown in FIGS. 3 and 4, the rear portion is obtained (e.g. by an injection moulding process) in one piece with the bristle elements 5 a, whereas the reliefs or plugs 8 a are inserted into, or in any way anchored to respective seats formed between the rear portion and the bristles.

The bristle elements are preferably made of a resin material selected from the group comprising thermoplastic resins, such as thermoplastic polyamides (nylon), thermoplastic polyesters (e.g. the Desmopan product made available by the company Bayer S.p.A.), thermoplastic polyurethanes (e.g. Texin made available by Bayer S.p.A.), casting resins, such as polyester polyols (Desmophen made available by Bayer S.p.A.), casting polyester resins, casting epoxy resins, casting silicone resins, resins obtained by a vulcanization process, e.g. vulcanized rubbers.

Optionally, a filler material can be added which is selected from the group comprising:

-   -   mineral fillers, such as calcium carbonates, kaolins, talc,         glass fibres, carbon fibres; and     -   abrasive fillers, such as industrial diamond, corunda; zirconium         oxides, tin oxides, aluminium oxides; and silicon, tungsten,         aluminium, titanium or boron carbides,

in a percentage ranging from 40% to 60%.

The reliefs are made of a resin material selected from the group comprising:

-   -   polyester, vinylester, epoxy resins, amine-hardener catalyzed         epoxy resins and high-hardness polyurethane resins;     -   thermoplastic resins, such as polyphenylensulphide (PPS),         polyamide (PA6, PA66, PA12), copolyamide (PAc), polysulphone         (PSU), polyethersulfone (PESU), polyetheretherketone (PEEK); and     -   phenolic resins.

Also the relief or block portions can be added with a filler material selected from the group referred to above in relation with the bristle elements.

Preferably, the bristle elements have a hardness ranging from 50 Shore A degrees to 30 Shore B degrees, whereas the reliefs have a hardness ranging from 50 Shore B degrees to 90 Shore B degrees.

The bristle elements can also have a different height from the reliefs.

Both the bristle elements and the reliefs can be obtained through injection processes, e.g. injection moulding, or a casting process.

A resin material, for example, can be cast into a cavity in a mould, whereby obtaining the reliefs, that once hardening thereof has been completed can be located in a second mould, where the bristle elements can be over-moulded by means of an injection press.

Advantageously, a thermosetting resin binder, e.g. having a 87 Shore hardness, can be used to obtain the reliefs, whereas a thermoplastic resin binder, e.g. Nevitane 250 D, made available by the company Nevitane S.p.A. at Luzzane (Reggio Emilia—Italy), filled with Ca 12%, can be used for the bristles. More advantageously, the thermosetting resin binder used to obtain the reliefs has a granule size one degree-lower than the thermoplastic resin binder used to obtain the bristles.

Advantageously, either the bristle elements or the plugs have a granule size ranging from 980 to 1 micron.

The reliefs in a tool according to the present invention are substantially rigid and designed to polish surface portions of blocks or slabs made of stone material, whereas the bristle elements are partly resilient and designed to work portions of a block or slab that could not be reached by the reliefs, the bristle elements being suitable for penetrating interstices in the material being worked. In view of this, a tool 1 or 10 according to the present invention can work the whole surface of a slab or block engaged by tool working front, whereby even a single working step of a honing machine working head is satisfactory to obtain an optimum finishing or lapping working.

Preferably, the bristle elements (5, 5 a) and reliefs (8, 8 a) delimit a substantially convex surface-working front.

A tool according to the present invention can be used for working materials having flat faces, even if they are porous in nature or formed with relatively small depressions therein, since the bristle elements can work pores and depressions as well.

The tool as described above is susceptible to numerous modifications and variations within the protection scope of the present invention as defined by the claims. 

1. A finishing and/or polishing block-like tool of abrasive material, which includes at least one front working portion and at least one rear portion designed to be anchored to a working head of a honing machine or a handle rear portion, wherein said at least one front working portion comprises: at least one first brushing working portion including a plurality of bristle elements each extending from said rear portion through a length many times greater than the thickness thereof; and at least one second working portion including depressions separated by at least one raising zone having size many times greater than the thickness of one bristle element.
 2. A tool as claimed in claim 1, wherein said at least one brushing working portion has a hardness that differs from that of said at least one second working portion.
 3. A tool as claimed in claim 1, wherein each first brushing working portion and each second working portion comprises bristle elements and reliefs, respectively, that extend to different levels.
 4. A tool as claimed in claim 1, wherein each first brushing working portion and each second working portion has bristle elements and reliefs, respectively, delimiting a substantially convex surface-working front.
 5. A tool as claimed in claim 1, wherein said at least one brushing working portion has a hardness ranging from 50 Shore A degrees to 30 Shore B degrees.
 6. A tool as claimed in claim 1, wherein said at least one second working portion has a hardness ranging from 50 Shore B degrees to 90 Shore B degrees.
 7. A tool as claimed in claim 1, wherein said at least one first brushing working portion and said at least one second working portion are made of different materials.
 8. A tool as claimed in claim 1, wherein said at least one first brushing working portion is made of a material selected from the group comprising thermoplastic resins, such as thermoplastic polyamides, thermoplastic polyesters, thermoplastic polyurethanes, casting resins, such as polyester polyols, casting polyester resins, casting epoxy resins, casting silicone resins, resins obtained through a vulcanization process, such as vulcanized rubbers.
 9. A tool as claimed in claim 1, wherein said at least one second working portion is made of a material selected from the group comprising: polyester, vinylester, epoxy resins, amine-hardener catalyzed epoxy resins and high-hardness polyurethane resins; thermoplastic resins, such as polyphenylensulphide (PPS), polyamide (PA6, PA66, PA12), copolyamide (PAc), polysulphone (PSU), polyethersulfone (PESU), polyetheretherketone (PEEK); and phenolic resins.
 10. A tool as claimed in claim 8, wherein said at least one first and/or second portion comprises at least one filler material in a percentage ranging from 40% to 60%, selected from the group comprising: calcium carbonates, kaolins, talc, glass fibres, carbon fibres, industrial diamond, corunda, zirconium oxides, tin oxides, aluminium oxides, and silica, tungsten, aluminium, titanium or boron carbides.
 11. A tool as claimed in claim 9, wherein said at least one first and/or second portion comprises at least one filler material in a percentage ranging from 40% to 60%, selected from the group comprising: calcium carbonates, kaolins, talc, glass fibres, carbon fibres, industrial diamond, corunda, zirconium oxides, tin oxides, aluminium oxides, and silica, tungsten, aluminium, titanium or boron carbides.
 12. A tool as claimed in claim 1, wherein said at least one second portion is made of a material having granule size one degree-lower than that of the material used to obtain said first portion. 